Question

I have created two expand bars under TabFolder in SWT. And I set the layout for the tab foloder as FillLayout(SWT.HORIZONTAL). It is showing two expand bars in the tabfolder.
But when I changed the tab folder into CTabFolder with the same layout it does not show me
any expandbars under the CTabFolder. What could be the issue? Do I need to set any parameter for that? Please see my below code for TabFolder and CTabFolder.

Code for TabFolder:

public class Snippet223 {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("ExpandBar Example");
        final TabFolder folder = new TabFolder(shell, SWT.BORDER);
        folder.setLayout(new FillLayout(SWT.HORIZONTAL));
        ExpandBar bar = new ExpandBar(folder, SWT.V_SCROLL);
        ExpandBar bar1 = new ExpandBar(folder, SWT.V_SCROLL);
        Image image = display.getSystemImage(SWT.ICON_QUESTION);
        // First item
        createContentsForExpandableBar(bar, image);
        createContentsForExpandableBar(bar1, image);
        shell.setSize(400, 350);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static void createContentsForExpandableBar(ExpandBar bar,
            Image image) {
        Composite composite = new Composite(bar, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.marginLeft = layout.marginTop = layout.marginRight = layout.marginBottom = 10;
        layout.verticalSpacing = 10;
        composite.setLayout(layout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        button = new Button(composite, SWT.RADIO);
        button.setText("SWT.RADIO");
        button = new Button(composite, SWT.CHECK);
        button.setText("SWT.CHECK");
        button = new Button(composite, SWT.TOGGLE);
        button.setText("SWT.TOGGLE");
        ExpandItem item0 = new ExpandItem(bar, SWT.NONE, 0);
        item0.setText("What is your favorite button");
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        item0.setControl(composite);
        item0.setImage(image);
    }

}

Code for CTabFolder:

public class Snippet223 {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("ExpandBar Example");
        final CTabFolder folder = new CTabFolder(shell, SWT.BORDER);
        folder.setLayout(new FillLayout(SWT.HORIZONTAL));
        ExpandBar bar = new ExpandBar(folder, SWT.V_SCROLL);
        ExpandBar bar1 = new ExpandBar(folder, SWT.V_SCROLL);
        Image image = display.getSystemImage(SWT.ICON_QUESTION);
        // First item
        createContentsForExpandableBar(bar, image);
        createContentsForExpandableBar(bar1, image);
        shell.setSize(400, 350);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static void createContentsForExpandableBar(ExpandBar bar,
            Image image) {
        Composite composite = new Composite(bar, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.marginLeft = layout.marginTop = layout.marginRight = layout.marginBottom = 10;
        layout.verticalSpacing = 10;
        composite.setLayout(layout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        button = new Button(composite, SWT.RADIO);
        button.setText("SWT.RADIO");
        button = new Button(composite, SWT.CHECK);
        button.setText("SWT.CHECK");
        button = new Button(composite, SWT.TOGGLE);
        button.setText("SWT.TOGGLE");
        ExpandItem item0 = new ExpandItem(bar, SWT.NONE, 0);
        item0.setText("What is your favorite button");
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        item0.setControl(composite);
        item0.setImage(image);
    }

}

Answer 1

You’ll need to create a TabItem/CTabItem under the TabFolder/CTabFolder and add the content to that. You shouldn’t be setting a layout on the tab folder itself. From the JavaDoc for CTabFolder:

Note that although this class is a subclass of Composite,
it does not make sense to set a layout on it.